Class I Human Leukocyte Antigens (HLA) is found on the surface of virtually every cell. Their function is to convey intracellular fitness to lymphocytes that cannot otherwise access intracellular spaces in order to detect viruses. Class I HLA molecules expose a viral infection by first sampling peptide fragments of proteins within the cell. Class I molecules then egress to the cell surface and display these intracellular protein snippets to T lymphocytes. Cytotoxic T lymphocytes which continuously scan class I HLA at the cell surface are able to single out class I HLA carrying virus-derived peptides and then destroy infected cells. Class I HLA reveals intracellular viruses by presenting viral peptide epitopes at the cell surface. Our laboratory is devoted to identifying those peptide epitopes unique to infected cells. We posit that the accurate discovery of viral epitopes unique to infected cells will facilitate the successful downstream development of viral therapeutics. To test this hypothesis, we propose to discover class I HLA presented peptide epitopes unique to West Nile Virus (WNV) infected cells in aim 1 of this project. We will identify WNV epitopes in multiple class I HLA using hollow fiber biorectors and mass spectroscopy. In order to initiate therapeutic development of the epitopes we find unique to WNV infected cells, in aim 2 we propose the generation of monoclonal antibodies to WNV/HLA class I complexes that distinguish infected cells. The development of mAb to WNV/HLA complexes in aim 2 will proceed through collaboration with Receptor Logic, a biotech firm proficient in the production of mAb to HLA/peptide complexes. The overall objective of this project is to therapeutically target WNV infected cells with mAb, and in aim 3 we will test these mAb for their ability to destroy WNV infected cells in vivo. HLA transgenic mice will be infected with WNV, mAb to WNV peptide/HLA complexes will be passively administered, and the antibody-mediated destruction of virus-infected cells will be evaluated.